Helical video tape insert recording editing method with flying erase head and servo control

Abstract

Disclosed is a helical scan video tape recorder having a flying sense head located upstream from a flying erase head and further upstream from a flying record/playback head. By employing a separate sense head to detect synch pulses, tension and relative speed of the video tape are controlled so as to eliminate synchronization errors in consequence of editing operations.

What is claimed is: 
     
       1. A method for controlling tape tension and relative speed during recording editing of a prerecorded video tape on a helical video tape recorder employing a flying erase head and having means for tape tension and relative speed control and including a standard timing signal source, comprising the steps of: placing said helical video tape recorder into an insert recording editing mode:   detecting horizontal synchronization signals embedded in the diagonal tracks on said prerecorded video tape prior to flying erasure of video information to be replaced;   comparing said embedded synchronization signals with timing signals from said standard source to develop an error signal proportional to the timing difference therebetween; and   controlling responsive to said error signal the tape tension and relative speed of said helical video tape recorder so as to diminish said error signal.   
     
     
       2. A method for recording editing by insertion of a selected video segment onto a video tape prerecorded on a helical tape recorder employing a flying erase head while controlling the tension and relative speed of said video tape comprising the steps of: placing said helical tape recorder into an insert recording editing mode:   detecting synchronization signals embedded in the diagonal tracks on said prerecorded video tape prior to flying erasure of video information to be replaced;   controlling tape tension and relative speed in response to signals obtained from said detecting step; and   recording on said video tape said selected video segment in place of prerecorded material.   
     
     
       3. A method for recording editing by insertion of a selected video segment onto a video tape prerecorded on a helical tape recorder employing a flying erase head while controlling the tension and relative speed of said video tape comprising the steps of: placing said helical tape recorder into an insert recording editing mode;   detecting horizontal synchronization signals embedded in the diagonal tracks of said prerecorded video tape prior to flying erasure of video information to be replaced;   controlling tape tension and relative speed in response to signals obtained from said step of detecting;   erasing portions of said prerecorded tape after said step of detecting; and   recording on said erased video tape said selected video segment in place of erased material.   
     
     
       4. In a helical video tape recorder system having means for tape tension and relative speed control, employing a flying erase head and including a standard timing signal source for line synchronization pulses: a method for recording editing by insertion of a desired video segment onto a tape carrying a video signal which includes prerecorded synchronization pulses on diagonal tracks thereof comprising the steps of: placing said helical video tape recorder system into an insert recording editing mode;   detecting said prerecorded synchronization pulses;   developing an error signal responsive to the difference between said detected synchronization pulses and a timing signal from said standard timing source;   applying said error to said means for tape tension and relative speed control to reduce said error signal;   erasing by means of said flying erase head a portion of said prerecorded video signal on individual tracks after said step of detecting said prerecorded synchronization pulses; and   recording on the erased portion of said video tape said desired video segment.   
     
     
       5. The method of claim 4 wherein said error signal is responsive to the timing difference between said detected line synchronization pulses prerecorded on said video tape and timing pulses from said standard timing source.